package api;

import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONUtil;
import lombok.SneakyThrows;
import model.Article;
import util.AppVar;
import util.DBUtils;
import util.ResultUtil;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

@WebServlet("/artlist")
public class ArticleListServlet extends HttpServlet {
    @SneakyThrows
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
      List<Article> data=new ArrayList<>();
      String msg="未知错误！";
        //1.得到前段参数并校验
        String currPage=req.getParameter("cp");
        String pageSize=req.getParameter("ps");
        int cp=1;//当前页码
        int ps=2;//每页显示的最大数
        if(!StrUtil.isBlank(currPage)){
            cp=Integer.valueOf(currPage);
        }
        if(!StrUtil.isBlank(pageSize)){
            ps=Integer.valueOf(pageSize);
        }
        //2.使用分页查询，查询数据库得到数据
        Connection connection= DBUtils.getConnection();
        String sql="select * from article order by aid limit ? offset ?";
        PreparedStatement statement=connection.prepareStatement(sql);
        statement.setInt(1,ps);
        statement.setInt(2,(cp-1)*ps);
        ResultSet resultSet=statement.executeQuery();
        while(resultSet.next()){
            Article article=new Article();
            article.setAid(resultSet.getInt("aid"));
            article.setTitle(resultSet.getString("title"));
            String ctime=resultSet.getString("createtime");
            article.setCreatetime(ctime.substring(0,ctime.lastIndexOf(".")));
            String context= resultSet.getString("context");
            context=context.replace("#","");
            int maxSize=Integer.min(50,context.length());
            article.setDesc((context.substring(0,maxSize)));
            data.add(article);
        }
        msg="";
        DBUtils.close(resultSet,statement,connection);
        //3.将数据返回给前端
        resp.setContentType(AppVar.RESPONSE_CONTENTTYPE_JSON);
        resp.getWriter().println(JSONUtil.toJsonStr(ResultUtil.toResult(
                200,data,msg)));
    }
}
